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APPLICATION NOTE
by A. RussoB. Bancal
J. Eadie
INTRODUCTION
The ever increasing demand for costreduction and higher levels of circuitcomplexity and reliability have directed thesemiconductor manufacturer’s attentiontowards smart power technologies which
allow the production of totally integratedmonolithic circuit solutions that include apower stage, control, driving and protectioncircuits on the same chip.
HIGH SIDE DRIVERS
power transistor on the same chip. Thepower handling capability of this type ofstructure compares favourably withmonol i th ic smart power devices ofequivalent chip size which use lateral, or"U-turn" power output structures.
Vertical intelligent power, (VIPower TM) anSGS-THOMSON Microelectronics patentedtechnology, established over 7 years ago,uses a fabrication process which allows theintegration of complete digital and/oranalog control circuits driving a vertical
1/24AN514/1092
The VIPower technology M0 used formaking these High Side Drivers producesa monolithic silicon chip which combinescontrol and protection circuitry with a
standard power MOSFET structure wherethe power stage current flows verticallythrough the silicon.
CROSS SECTION OF MØ VIPower TM TECHNOLOGY
High Side Drivers, with their integratedextra features are power switches that canhandle high currents and work up to about40V supply voltage. They require only asimple TTL logic input and incorporate afault condition status output. They can
drive an inductive load without the need fora freewheeling diode. For completeprotection the devices have an over-temperature sensing circuit that will shutdown the chip under over-temperatureconditions. They also have an under-
SMART POWER APPROACHES
2/24
Driving circuitry
Power stage output
Enhancement and depletion NMOS
Power stage
VDMOS
APPLICATION NOTE
voltage shutdown feature. It is simple tointroduce some differences in the controllogic to produce devices with featureswh ich ca te r f o r d i f f e ren t wo rk ingenvironments.
Each application exerts an externalinfluence over the switch. A filament lampor DC motor, for example, have in-rushcurrents that any switch has to handle.Solenoids and motors have an inductiveef fec t and must lose the res idua lmagnetism when the current is turned off.This gives rise to induced voltages and theneed to remove this stored energy.External fault conditions can also stressthe drivers and their associated circuitry.The fol lowing discussion has beendesigned to explain the basic principlesinvolved in using these devices and tohelp to understand how they reactunder the influence of various applications.
Almost every electronic switch used in amodern automobile application is a highside switch. This configuration ispreferred for automotive use because:
a) - This configuration protects the loadfrom continuous operation and resultingfailure, if there is a short circuit to theground. Since the body of a car is metaland 95% of the total car is ground, theshort to ground is much more commonthan short to VCC
b) - High Side Drivers cause lessp r o b l e m s w i t h e l e c t r o c h e m i c a lcorrosion. It is of primary importancein automotive systems because theelectrical components are in an adverseenvironment, specif ically adversetemperatures and humidity and thepresence of salt. For this reason theseries switch is connected between theload and the positive power source.Therefore when the electr ical
component is not powered (that is forthe greatest part of the lifetime of thecar) it is at the lowest potential andelectrochemical corrosion does not takeplace.
Integrated High Side Dr ivers of fernumerous advantages over the popularautomotive relay used in cars today.Diagnostic information output from theHigh Side Driver helps the on-boardmicrocontroller to quickly identify andisolate faults saving repair time and oftenimproving safety. High Side Drivers canreduce the size and weight of switchmodules, and where multiplexed systemsare used, dramatically reduce the size ofthe wiring harness.
Process control applications offer anotheruse for High Side Drivers. A considerableimprovement in reliability and reduction indown time can be obtained by using themin place of relays. Process controlsystems, often consisting of powerfulcomputers that control large numbers ofactuators, are perfect environments forthese dev ices. The semiconductormanufacturer has little control over thenature of the load being driven and thesecan vary - solenoids, motors, transducers,leds. In these situations, software processmonitoring by a µP can detect a faultreported by a status output and offers theoption of taking corrective action. In theunlikely event of a failure in a High SideDriver in critical processes, a seconddevice can be programmed to operateinstead.
SGS-THOMSON High Side Drivers aredesigned to provide the user with simple,self protected, remotely controlled powerswitches. They have the general structureas shown in figure 1. Appendix I shows atable of the devices and summarizes theirfeatures.
3/24
APPLICATION NOTE
Figure 1 : Standard current and voltage conventions
THE GENERAL FEATURES OF HIGHSIDE DRIVERS.The diagram in figure 3 shows the controland protection circuit elements and the
power stage of a basic device.
Figure 2 : High Side Drivers interfaces between control logic and power load
Some typical applications are shown in figure 2.
4/24
APPLICATION NOTE
Figure 3 : Generic Internal Block Diagram
InputThe 5V TTL input to these High SideDrivers is protected against electrostaticdischarge. General rules concerning TTLlogic should be applied to the input. Theinput voltage is clamped internally at about6V. It is possible to drive the input with ahigher input voltage using an externalresistor calculated to give a current notexceeding 10mA at the input.
Internal power supplyTo accommodate the wide supply voltagerange experienced by the logic and controlfunctions, these devices have an internalpower supply. Some parts of the chip areonly active when the input is high, thestatus output and charge pump forexample. This means it is possible toconserve power when the device is idle.The internal power supply has thereforebeen designed in two parts. One sectionsupplies power to the basic functions ofthe chip all the time, even when the inputis 0V. The second section supplies poweronly when the input is high. This ensuresthat the stand-by current is limited to 50µAmaximum in the off-state.
THE CONTROL CIRCUIT.Under voltage lock-out.Under-voltage protection occurs when thesupply voltage drops to a low levelspecified in the datasheet as VUSD. Theunder-voltage level set at this valueensures the device functions correctly.Inductive effects must be considered inunderstanding the function of this feature.The di/dt is controlled by the device andnot by the external circuit. The controlledvalue is calculated for a line inductance of5µH( 5mt. of wire). Typically di/dt=0.5A/µsfor a normal load and 1A/µs for a shortcircuit. At turn on this generates anopposing voltage. If this opposing voltageis too large, the apparent supply voltagewill drop below the under-voltage lock-outlevel and the device will turn off. Usingthe specified conditions, the inducedvoltage will not be large enough to reducethe supply voltage below 6V. This isimportant in the case where the load is anear short circuit when in-rush currentoccurs, as in the case of a car headlampfilament turning on.
* Optional feature in the VNXXAN series
5/24
APPLICATION NOTE
Open load detection and stuck-on toVCC.Open load detection occurs when the loadbecomes disconnected. In the VN20Nfamily open load detection only occurs inthe on-state.
An extra feature for load disconnectiondetection is that open load detection duringthe off-state as well as in the on-state canbe provided. The circuit for the off-stateopen load detection requires an externalresistor between VCC and the output pin.
Figure 4 : Equivalent Schematic for the open load detection current in off-state
Over-temperature protectionOver-temperature protection is based onsensing the chip temperature only. The
location of the sensing element on the chipin the power stage area, ensures thataccurate, very fast, temperature detectionis achieved. The range within whichover - tempera ture cu tou t occurs is140°C - 180°C with 160°C being a typicallevel.
Over-temperature protection acts toprotect the device from thermal damageand consequently also limits the averagecurrent when short circuits occur in theload.
Open load detection is possible in the off-state in the VN21 family and it conformsto the I .S.O. norms for automotiveapplications. If an open load condition isdetected the status flag goes low. Shouldan external supply be applied to the load(output pin) or the device is externally shortcircuited, the off-state open load detectioncan detect this “stuck-on” to VCC condition.
6/24
APPLICATION NOTE
Figure 5 : VN20N Die Layout - Note the thermal sensor inside the Power MOSFET Area
Driving the power MOSFET.The power MOSFET output stage is drivenby an internally generated gate voltage. Acharge pump provides sufficient voltage toturn on the gate.
Turn-onAs previously explained, the High Side
Drivers are turned-on with a controlleddi/dt.
Turn-off: Normal and fast loaddemagnetizationWhen a High Side Driver turns off aninductance a reverse potential appearsacross the load. z
Figure 6 : Inductive load demagnetization turn-off for the VN20N family
7/24
APPLICATION NOTE
The source of the power MOSFETbecomes more negative than the grounduntil it reaches the demagnetizationvoltage, Vdemag., of the specific device. Inthis condit ion the inductive load isdemagnetized and its stored energy isd i ss ipa ted in the power MOSFETaccording to the equation shown below:
VN20N VN21
In the basic High Side Driver family thetypical value of, Vdemag. is = 4V.
In the I.S.O. and industrial series,to reducethe dissipated energy, an internal circuithas be added in order to have a typicalVdemag. = 18V.
In this condition the stored energy isremoved rapidly and the power dissipationin the power MOSFET is reduced - seeequation. Figure 7a/b compares thewaveforms of the normal and fastdemagnetization techniques.
Figure 7a/b : VN20N-VN21 Driving an Inductive Load
[Vcc +Vdemag.]Pdemag.= 0.5 Lload [Iload]² ⋅ ------------------- ⋅ f Vdemag.
where f is the switching frequency and Vdemag. the demagnetization voltage.
Figure 7b shows the VN21 driving aninductive load. During the on period, thecurrent in the load rises linearly to amaximum. At turn-off the current decreaselinearly, but, at a sufficiently fast rate forfast demagnetization of the load. Thereis no fault output from the status pin. Inthe VN20N, the basic High Side Driverw i t h n o s p e c i a l f e a t u r e f o r f a s tdemagnetization, the turn-off takes up to 5times longer than the VN21. Note that thestatus output will pulse at turn on becausethe internal circuit detects a very shortduration open load, see figure 7a.The maximum inductance which causes
8/24
the chip temperature to reach the shutdown temperature in a specified thermalenvironment, is a function of the loadcurrent for a f ixed VCC, Vdemag. andswitching frequency. This is the maximumra te a t wh ich the d r i ve rs can bedemagnetized. Figure 8 shows themaximum inductance for a given loadcurrent for devices meet ing I .S.O.r e q u i r e m e n t s , a s s u m i n g a c h i ptemperature of 160°C at turn-off and asupply voltage of 13V. The values are fora single pulse with 85°C case temperature.Note that the devices are not protectedagainst overtemperature during turn-off.
APPLICATION NOTE
Figure 8 : Max inductance which produces a temperature of 160°C at turn off with Vcc = 13V. The values are for a single pulse with Tc = 85°C
Additional Features of the High SideDriversHigh Side Drivers are designed for use invarious market segments, the preciserequirements of the drivers varying a littlewith the application. There are additionalf e a t u r e s t o a c c o m m o d a t e t h e s erequirements.
To reduce the on-state quiescent currentfor some applications, particularly industrialones, the open load detection circuit is notincluded. There will consequently also be alower power dissipation, an important pointwhen similar, multiple High Side Driversare mounted on one board. It can meansthe difference between using or not usinga heatsink.
9/24
CONDITIONS: VCC = 13V TC = 85°C
APPLICATION NOTE
The operating voltage range can vary e.g.5.5V to 26V for automotive applicationsand 7V to 36V for process control. Somedevices have fast demagnetization of theload, ground disconnection protection,on- and off- state open load detection and5ms filtering of the status output.
Status output and status output signalfiltering.The difference in electrical behaviourbetween the non-filtered and the filteredHigh Side Drivers is that the status outputfiltering circuit provides a continuous signalfor the fault condition after an initial delayof about 5ms in the filtered version. Thismeans that a disconnection during normaloperation, with a duration of less than 5msdoes not affect the status output. Equally,any re-connection during a disconnectionof less than 5ms duration does not affectthe status output. No delay occours for thestatus to go low in case of overtemperatureconditions. From the falling edge of theinput signal the status output initially low infault condition (overtemperature or openload) will go back high with a delay tPOVL incase of overtemperature condition and adelay tPOL in case of open load. Thesefeatures fully comply with InternationalStandards Office, (I.S.O.), requirements forautomotive High Side Drivers.
ABNORMAL LOAD CONDITIONS:
Load short circuitsShould a load become short circuited,various effects occur and certain stepsneed to be taken to deal with them,particularly choosing the correct heatsink.Two clear cases of short circuit occur: 1. The load is shorted at start-up. 2. The load becomes short during the on-state.
Start-up with the load short circuited.At turn-on the gate voltage is zero andbegins to increase. Short circuit currentstarts to flow and power is dissipated in theHigh Side Driver according the formula:
Pd = VDS x ID
The effect is to cause the silicon to heatup. The power MOSFET stays in the linearregion. When the silicon temperaturereaches about 160°C the over temperaturedetection operates and the switch is turnedoff. Passive cooling of the device occursuntil the reset temperature is reached andthe device turns back on again. The cycleis repetitive and stops when the power isremoved, the input taken low or the shortcircuit is removed.
Figure 9 : Automatic Thermal cycle at start - up with the load short - circuited.
10/24
APPLICATION NOTE
Even in this configuration, the devicecontrols the di/dt. Figure 9 shows astart-up when there is a short circuited loaddriven by a VN05N. The initial peak currentis 30A for this 180mΩ device.
A short circuit occurring during the on-state.When a short circuit occurs during the
on-state, the power MOSFET gate isalready at a high voltage, about VCC+ 8V,so the gate is hard on. Hence the shortcircuit di/dt is higher than in the first case,and only controlled by the load itself. Afterthe steady state thermal condition isreached, thermal cycling is the same as inthe previous case.
Figure 10 : Automatic thermal cycle for a short circuit occouring during the on - state
The thermal cycling in overload conditionsproduces repetitive current peaks. Thedevice switches on, the silicon heats upuntil the over-temperature sensing acts to
Figure 11 : Automatic Thermal cycle in overload condition
Automatic thermal cycle.turn the device off. The rate of passivecooling depends on the thermal capacity ofthe thermal environment. This, in turn,determines the length of the off-stateduring thermal cycling.
11/24
APPLICATION NOTE
It is important to evaluate the average andRMS current during short circuit conditions.This is required in order to determine thetrack dimensions for printed circuit boardsand the correct value for any fuse used.In all practical situations there is no dangerto pcb tracks from these high peak currentfor track designed to handle the nominalload current.
Evaluating the Average currentIn steady state conditions the junctiontemperature osc i l la tes between T j(shutdown) and Tj (reset).
Tj(av.)=(Tj(shutdown)+Tj(reset))/2 ≈ 135°C
Dissipated power:
PD = I(AV) x VCC
For a specific package
PD = (TJ(AV) - Tcase) / Rthj-case
I(AV)=(TJ(AV) - Tcase ) / (Rthj-case x VCC)
Evaluating the RMS currentThe RMS current, IRMS, generates heat inthe copper track on PCBs during shortcircuits.
T
I(RMS)2 = 1/T 0 I2(t)dt
I(RMS) = I(PK) x √Θ /T, where Θ/T is the duty cycle.
T
with I(AV) = 1/T 0 I(t)dt = I(PK) x Θ/T
I(RMS) = √ (I(PK) x I(AV))
Note that Iaverage does not depend on thepeak current I(PK) .
Example:VN21 with Tcase = 85°C has an averagecurrent, I(AV) = 3.85A, at Rthj-case = 1°C/W and VCC = 13VThe average current is independent of thepeak current.Generally, a current limiter does notdecrease the average current.
Figure 12 : Average current during an hard short - circuit test
Θ
∫
12/23
∫
APPLICATION NOTE
Θ
The RMS current increases proportionallyto the square root of the peak current -->+40% if I(PK) is doubled. Schemes to limit
the current do not decrease the RMScurrent significantly.
Heatsink requirements.Overload protection is based on deviceheating. I f you want to detect anoverload, i.e a damaged load, the chipmust be allowed to heat up so that thethermal sensor located on the chip isactivated. This leads to the followinggeneral rules for sizing heatsinks for theVN High Side Drivers.
1.Do not use a too big heatsink.2.Do not use a VN device which has RON much lower than that which the application requires.
This example illustrates a specific case.
Situation:- a supply voltage of 14V,- a load resistance of 2Ω,- VN20N - RDS(on) at 25°C = 50mΩ- load current = 7A
To detect an over current of 20A,
Figure 13 : RMS current during an hard short-circuit test
13/24
assuming that RDS(on) at 150°C = 100mΩ(see datasheet) hence:
PD = (20)2 x 100 x 10-3 = 40W
Rthj-a should be dimensioned for
Θthermal shutdown - ΘAmbient < PD x Rthj-a.
For example 160°C - 25°C < 40W x Rthj-a
The effects of load disconnection.When a load becomes disconnected therecan be over-voltages caused by thechange of load current. Figures 14a/bsummarizes the likely effects. Figure 14a,shows a load driven by a VN21. The supplyto the VN21 has a very low parasiticinductance. When the load becomesdisconnected, the current changes at arate determined by the time taken for theload to disconnect. This controls di/dt .
APPLICATION NOTE
Figure 14a/b : Example of possibles situations during a load disconnection
Figure 14c : Behaviour of a VN21 during a load disconnection
connection pins are likely to have someinductance, to use a 56V zener diode or acapacitor close to the supply pin of theswitch. Figure 14c shows a test madeusing a zener clamp to overcome lineinductance.
PROTECTION AGAINST GROUNDDISCONNECTIONThere are a number of distinct situationsthat can occur when one of the groundconnections is broken in circuits using theHigh Side Drivers.
The first case, shown in fig. 15a, is whenthe GND pin of the High Side Driver is
In this present case, there is virtually noinductance in the supply line. Hence noover-voltage is generated and Vcc isunaffected. The status pin goes low toindicate an open-load state
In the second case illustrated, figure 14b,the supply line has parasitic inductanceand capacitance. When the load isdisconnected an over-voltage is generated,(Vover-voltage = L di/dt). The di/dt is notcontrolled by the device but by how fastthe load is disconnected. It is possible thatthe ove r -vo l tage may exceed thebreakdown voltage of the device. It is awise precaut ion where the supp ly
14/24
TEST CONDITIONS: LINE INDUCTANCE +++++ 46 VOLTS CLAMPING DEVICE
APPLICATION NOTE
disconnected while the µC and the loadare connected to ground. In this case inthe I.S.O. and industrial High Side Driversnothing happens and the device remainsoff. In the VN20N family a voltage of about
2V appers on the load and conseguentlythere is a power dissipation:PD = (VCC - 2) ⋅ ILOADusually very low. In these conditions thediagnostic is not functioning.
Figure 15a : Possible ground disconnection occurring when a High Side Driver is connected to a µController (case 1)
state at VCC. In the VN20N family a voltageof about 4V appears on the load andconseguently there is a power dissipation:PD = (VCC - 4) ⋅ ILOADIf PD is excessive with respect to theheatsink capability, destruction may occurssince the protections are not functioning.The load is permanently activated.
The second case, shown in fig. 15b, iswhen both the GND pins of the High SideDriver and of the µC are disconnectedwhile the load is connected to ground. Inthis situation the signal GND rises up toVCC. In the I.S.O. and industrial High SideDrivers nothing happens up to VCC<18Vand the diagnostic output remains in high
Figure 15b : Possible ground disconnection occurring when a High Side Driver is connected toa µController (case 2)
15/24
APPLICATION NOTE
Another practical case is when an externalcomponent supplies current to the HighSide Driver GND pin which is disconnectedfrom the ground. This might occur if theVN device is mounted on a local PCB withother devices and has a local ground whilethe load may be grounded to the frame orbody of the equipment, figure 16. Also, inthis case, for internally protected devices,the output remains off up to the pointwhere the voltage on the GND pin is ≤ 18Vwith reference to real ground at 0V. Thiswill reduce the maximum VCC the High Side
Driver is able to withstand before turningon with the control circuit in-operative.One solution to this problem is to insert aresistor and diode in between the deviceGND pin and the output pin. The seriesresistor, Rs, must be calculated so that thesum of the current, Is, of the High SideDriver chip connected to the GND nodeplus the current drawn by the externalelements, produces a voltage drop of lessthan 18V across Rs + Ds + Rload for I.S.O.or industrial High Side Drivers and lessthan 2V for STD devices.
CONCLUSION
The VN series of High Side Drivers offersdesigners a highly attractive method ofcontrolling a variety of inductive andresistive loads. The option to use aselection of extra features such as fastdemagnetization or status filtering makesthem equally suitable for general orspecialised use, typically in the automotiveenvironment.
Figure 16 : Ground disconnection occuring when an equivalent resistor supplies current on the GND pin.
16/24
APPLICATION NOTE
60V B(BR)DSS HIGH SIDE DRIVERS PRODUCT RANGE
VIPower
VN02NVN05NVN20NVN30N
VN03VN06VN21VN31
DEVICE RDS(on)@ 25°C(mohm)
4001805030
5001805030
VCCRange
(V)
7 - 267 - 267 - 267 - 26
5.5 - 265.5 - 265.5 - 265.5 - 26
Pentawatt/PowerSO-10TM
"""
PACKAGE
Pentawatt/PowerSO-10"""
EXTRAFEATURES
35050
7 - 367 - 36
Pentawatt/PowerSO-10"
VN02ANVN20AN
20010060
6 - 266 - 266 - 26
Heptawatt/PowerSO-10"
Pentawatt/PowerSO-10
VN02H(*) 400 5 - 36 Pentawatt/PowerSO-10
∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗∗
VND05B(*)VND10B(*)VN16B(*)
(*) Application information as described in the Note apply also to these devices
Open load detection off state + stuck-on to VCC
Fast demagnetization & ground disconnection protection
5msec STATUS FILTERING (ISO STANDARD)
17/24
∗∗∗∗∗Double channel
APPLICATION NOTE
SC
HE
MA
TIC
CO
MP
ON
EN
T
VN
03V
N06
VN
21V
N31
RE
XT
If th
e lin
e in
duct
ance
is n
otze
ro a
nd d
i/dt
caus
ed b
ydi
scon
nect
ion
of t
he l
oad
is h
igh,
an
over
vo
ltage
E
=L⋅
di/d
t ap
pear
s on
VC
C,
The
V(B
R)D
SS o
f th
e ou
tput
pow
er M
OS
FE
T c
ould
be
exce
eded
.
D4
or C
1
D4
or R
LIM
It is
nec
essa
ry t
o se
t th
ecu
rre
nt
tha
t fi
xes
the
volta
ge
,VL
OA
D,
in
the
o
ffst
ate.
W
hen
RLO
AD f
ails
-g
oe
s o
pe
n
or
hig
hre
sist
ance
- V
LOA
D in
crea
ses
and
an in
tern
al c
ompa
rato
rtr
igge
rs th
e st
atus
flag
to g
olo
w.
CO
MM
EN
T
R LOAD<<10k
ΩΩΩΩ Ω
ALL
Use
a 5
6V z
ener
dio
de t
ocl
amp
VC
C o
r pu
t a c
apac
itor,
C1
(abo
ut 1
00nF
), n
ear
VC
Cpi
n.
ALL
D4
can
be u
sed
as a
dece
ntra
lized
cla
mp
(VC
Ccl
amp
and
ener
gy c
lam
p).
Oth
erw
ise
a re
sist
or, R
LIM
,ca
n
be
a
dd
ed
o
n
the
grou
nd p
in t
o lim
it t
hecu
rre
nt
in
the
si
gn
al
sect
ion
of t
he d
evic
e in
case
it e
xcee
ds th
e si
gnal
path
bre
akdo
wn
volta
ge.
NO
TE
S
RLI
M =
150
Ω is
a g
ener
al v
alue
to p
rote
ct d
evic
es f
rom
the
effe
cts
of a
load
dum
p. R
efer
to t
he s
peci
fic d
ata
shee
t.
SY
MP
TO
M
Off-
stat
e op
en lo
adde
tect
ion
1 2V
olt
ag
e
spik
e
on
V
CC
whe
n lo
ad d
isco
nnec
ts.
Ove
r vo
ltage
on
VC
C fr
omex
tern
al c
ircui
t3
18/24
Ω
DE
VIC
E
Cho
ose
RE
XT
to m
atch
VD
D to
fix I O
L(of
f). T
he th
resh
old
VLO
AD
is fi
xed
at V
RE
F.
I OL(
off)
= (
VD
D -
VR
EF)
/ RE
XT.
The
ope
n lo
ad d
etec
tion
inof
f-st
ate
is o
nly
poss
ible
for
a
no
min
al
valu
e
of
APPLICATION NOTE
19/24
VS
S=
GN
D
No
curr
ent a
ccro
ss in
put
→A
DC
cur
rent
flow
s in
the
If th
e lo
ad is
an
indu
ctan
ce w
itha
para
llel f
ree
whe
elin
g di
ode,
the
user
see
s 2
forw
ard
bias
eddi
odes
bet
wee
n G
RO
UN
D a
nd
Do
not e
xcee
d im
ax to
If th
e ba
ttery
is s
hort
circ
uite
d by
3 x
2 se
ries
diod
es (
typi
cally
an
alte
rnat
or d
iode
con
figur
atio
n)
CC
, is
clam
ped
to a
bout
-3V
and
no
dam
age
occu
rs to
the
VN
dev
ice.
for t
he d
evic
e is
-13V
. T
opr
even
t dam
age
to th
e de
vice
use
e
ith
er
a
bip
ola
r o
r
diod
e in
ser
ies
with
the
grou
ndpi
n co
nnec
tion.
Use
R1
and
R2
to lim
it the
neg
ativ
e cu
rren
tin
the
inp
ut a
nd s
tatu
s pi
nsbe
caus
e th
e in
tern
al g
roun
d
SC
HE
MA
TIC
CO
MP
ON
EN
TC
OM
ME
NT
NO
TE
S
ALL
*VC
C >
1V
→
MG
ND
"ON
"→
Nor
mal
cas
e*-
4 <
VC
C<
0
→M
GN
D O
FF
→
a
nd G
ND
pin
s
load
and
DB
ody
WA
RN
ING
:
VC
C.
→
p
reve
nt d
amag
e.
Re
fer
to
the
e
qu
iva
len
tsc
he
ma
tic
see
n
by
use
rth
roug
h pi
ns: L
oad,
Inpu
t, G
ND
ALL
Bat
tery
con
nect
ion
reve
rsed
;co
rrec
t co
nnec
tion
of
the
Hig
h S
ide
Driv
er d
evic
es.
the
su
pp
ly
volt
ag
e,V
D1
or D
2A
LLH
igh
Sid
e D
river
rev
erse
conn
ecte
d w
ith th
e ba
ttery
corr
ectly
con
nect
ed.
VC
C
Sch
ottk
y
drop
s to
VC
C.
SY
MP
TO
M
4S
uppl
y re
vers
al
5S
uppl
y re
vers
al -
cas
e 1
Sup
ply
reve
rsal
- c
ase
26
DE
VIC
E
APPLICATION NOTE
SC
HE
MA
TIC
CO
MP
ON
EN
T
RIN
PU
TD
rivi
ng
th
e
inp
ut
fro
m
avo
ltage
gre
ater
than
6V
R1
R2
Driv
ing
an in
duct
ive
load
, thi
ski
nd o
f di
scon
nect
ion
has
the
sam
e el
ectr
ical
effe
cts
as V
CC r
ever
sal.
CO
MM
EN
T
ALL
To
driv
e th
e in
put
from
a l
ine
volta
ge >
6V
ins
ert
a se
ries
resi
stor
to li
mit
the
inpu
t cur
rent
I IN m
ax <
10m
A
ALL
1) R
esis
tive
load
- n
o pr
oble
mof
dam
age.
VN
03V
N06
VN
21V
N31
VN
02A
NV
N20
AN
An
exte
rnal
com
pone
nt,R
eq,
supp
lies
curr
ent
to t
he H
igh
Sid
e D
river
GN
D p
in.
The
loca
l gro
und
is s
epar
ate
from
the
load
gro
und.
Th
e
de
vice
s a
re
inte
rna
llypr
otec
ted
(out
put
stag
e of
f) i
fth
e vo
ltage
on
the
GN
D p
in is
≤18
V w
ith r
efer
ence
to
the
real
grou
nd a
t Ø
V.
To
avoi
d th
eH
igh
Sid
e D
river
to
turn
-on
ifG
ND
is
over
18V
is
poss
ible
inse
rt R
s an
d D
s as
sho
wn
infig
ure.
Cho
ose
Rs
so t
hat
V1<
18V
SY
MP
TO
M
Inpu
t driv
ing.
Pin
dis
conn
ectio
n -
VC
C8
Pin
dis
conn
ectio
n -
Gro
und
97
20/24
2) In
duct
ive
load
- V
CC r
ever
sal
occ
urs
. If
cu
rre
nt
an
din
duct
ance
of
le
ads
are
to
oh
igh
th
e
de
vice
m
ay
be
dam
aged
but
th
e
safe
tym
argi
n is
wid
e -
up t
o 10
0mH
and
8A fo
r th
e V
N21
In t
his
case
, in
put
and
stat
uspi
ns a
re p
ulle
d to
a n
egat
ive
volta
ge s
o it
is r
ecom
men
ded
to in
sert
resi
stor
s in
ser
ies
with
thes
e pi
ns i
n or
der
to p
rote
ctth
eµC
.
NO
TE
SD
EV
ICE
APPLICATION NOTE
SC
HE
MA
TIC
CO
MP
ON
EN
T
ALL
Vol
tage
rang
e fo
r all H
igh
Sid
eD
river
s is
def
ined
bet
wee
nV
CCan
d V
SS
2 (V
Nxx
GN
D).
All
volta
ges
VIL
, V
IH,
VU
SD a
rere
fere
d to
VS
S2.
NO
TE
S
If V
SS
1 an
d V
SS
2 ar
e di
ffere
nt,
reca
lcul
ate
VIL
, V
IH,
VU
SD a
ndbe
war
e of
app
licat
ion
bugs
.(S
ee p
oint
s 11
/12/
13/1
4)
CO
MM
EN
T
ALL
D2
Usi
ng
p
ow
er
dio
de
to
with
stan
d re
vers
ed b
atte
ry.
Cas
e 1:
VS
S1
= V
SS
2 =
/= G
ND
with
VS
S1
> G
ND
Vol
tage
loss
es in
pow
er d
iode
.In
put
and
sta
tus
leve
ls a
ren
ot
eff
ect
ed
. U
nd
er-
volt
ag
esh
utdo
wn
leve
l in
crea
sed
bydi
ode
VF.
Off-
stat
e op
en lo
ad le
vel,
VR
EF,
incr
ease
d by
VF.
A g
ener
al r
ule
is:
leve
l sh
ift i
s(V
SS
2 -
GN
D).
D2
ALL
Usi
ng a
dio
de to
pro
tect
the
Hig
h
Sid
e
Dri
ver
ag
ain
stre
vers
ed b
atte
ry.
(See
poi
nt 6
abo
ve)
VS
S1
= V
SS
2 =
/= G
ND
with
VS
S1
> G
ND
Th
e
inp
ut
an
d
sta
tus
are
unaf
fect
ed.
VU
SD =
(V
SS
2 - G
ND
)+
VU
SD
o. O
ff-s
tate
ope
n lo
adle
vel,
VR
EF, i
s in
crea
sed
by (V
SS
2-
GN
D).
No
t su
ita
ble
if
th
eµC
on
tro
ller
use
s a
n
an
alo
gtr
ansd
ucer
ref
erre
d to
gro
und.
SY
MP
TO
M
Gro
und
pote
ntia
ldi
ffere
nces
10
Gro
und
pote
ntia
ldi
ffere
nces
- c
ase
111
Gro
und
pote
ntia
ldi
ffere
nces
- c
ase
212
DE
VIC
E
APPLICATION NOTE
21/24
22/24
SC
HE
MA
TIC
CO
MP
ON
EN
T
R1,
D2
CO
MM
EN
T
Usi
ng a
dio
de t
o pr
otec
t th
eH
igh
S
ide
D
rive
r a
ga
inst
reve
rsed
bat
tery
.
VS
S1
=/=
VS
S2.
VS
S2
> V
SS
1
VIL
and
VIH
shi
fted
by (
VS
S2
-V
SS
1).
R1
limits
any
neg
ativ
ecu
rren
t w
hen
the
µC
ontr
olle
rta
kes
I/O
to g
roun
d .O
n th
est
atus
pin
the
zero
cor
resp
onds
to t
he V
F o
f D
2, V
US
D a
nd V
OL
bein
g in
crea
sed
by (V
SS
2 - G
ND
).
R2,
D2
Usi
ng a
dio
de t
o pr
otec
t th
eµC
aga
inst
reve
rsed
bat
tery
.
VS
S1
=/=
VS
S2.
VS
S2
< V
SS
1
In f
ault
cond
ition
s th
e de
vice
pulls
the
sta
tus
pin
dow
n t
oV
SS
2 and
the
µCon
trol
ler s
ees
ane
gativ
e vo
ltage
- (
VS
S1 -
VS
S2)
.T
here
is a
risk
of l
atch
up
for t
heµC
ontr
olle
r CM
OS
out
put.
Add
R2
to
limit
the
curr
ent.
Und
ervo
ltage
and
off-
stat
e op
enlo
ad le
vels
are
not
shi
fted.
R1,
R2,
D2,
D7.
Rec
omm
ende
d sc
hem
e* c
omm
on g
roun
d fo
rµC
ontr
olle
r a
nd V
N d
evic
e*
Rev
erse
d ba
ttery
pro
tect
ion
-
Sch
ottk
y di
ode
* S
erie
s re
sist
or f
or in
put
and
s
tatu
s pi
ns*
Ove
r-vo
ltage
pro
tect
ion
- bi
-
dire
ctio
nal Z
ener
Gro
und
pote
ntia
ldi
ffere
nces
- c
ase
3
Gro
un
d
po
ten
tia
ldi
ffere
nces
- c
ase
4
13 14
Sum
mar
y
of
the
influ
ence
of
grou
nddi
ffere
nces
, pi
ndi
scon
nect
ions
and
over
vol
tage
pro
tect
ion.
15
ALL
ALLALL
NO
TE
SD
EV
ICE
SY
MP
TO
M
APPLICATION NOTE
23/24
SC
HE
MA
TIC
CO
MP
ON
EN
TC
OM
ME
NT
R1
In f
ull
bri
dg
e a
pp
lica
tion
sdu
ring
the
dem
agne
tizat
ion
phas
e V
LOA
D >
VC
C.
A c
urre
nt w
ill fl
ow o
ut o
f GN
Dpi
n, p
ossi
bly
dam
agin
g th
ebo
ndin
g.
ALL
D1
Hig
h
volt
ag
es
can
b
ege
nera
ted
if th
e ba
ttery
is
dis
con
ne
cte
d
wh
en
th
ege
nera
tor i
s ru
nnin
g in
a c
ar.
Da
ma
gin
g e
ffe
cts
can
be
ove
rco
me
b
y u
sin
g
acl
ampi
ng d
iode
with
at l
east
VB
R
>
26
V
as
2
x 1
2V
batte
ries
are
ofte
n us
ed t
oju
mp
st
art
ca
rs.
Th
is
for
over
volta
ge tr
ansi
ent h
ighe
rth
an s
peci
fied
in d
atas
heet
s.
Pro
tect
ion
agai
nst o
ver-
volta
ges
are
e
ffic
ien
t if
co
nn
ect
ed
betw
een
pin
3 (V
CC)
and
pin
1(g
roun
d).
ALL
Inse
rt
a
resi
sta
nce
, R
1(s
ugge
sted
val
ue 4
7Ω),
in
the
grou
nd p
in t
o lim
it th
e gr
ound
curr
ent a
nd a
void
dam
agin
g th
ebo
ndin
g.
DE
VIC
E
Lo
ad
d
um
p:
b
att
ery
disc
onne
ctio
n w
hils
t th
eal
tern
ator
is w
orki
ng
16
VLO
AD >
VC
C(B
ridge
circ
uit)
17
SY
MP
TO
MN
OT
ES
APPLICATION NOTE
APPLICATION NOTE
24/24
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